8 Maciteay Memorrat Vouvume. 
on the other hand, the hyoidean vessel arises from the first afferent artery, and thus 
carries venous blood. 
(b) From the anterior efferent artery of the second branchial arch (figs. 2, 
3, and 6). 
This vessel, like that of the first arch, does not end blindly. It is continued 
ventrad of the gill arch and forms a vessel which may be called the Lypodbranchial 
artery. 
This runs first of all towards the ventral surface and then turns backwards in 
front and ventrad of the second afferent vessel. It then divides into two branches, 
of which the first immediately turns dorsalwards and at the same time towards the 
median line. Passing dorsad of the 3rd and 4th afferent vessels and of the heart, it 
is distributed to the ventral wall of the cesophagus and forms the @sophageal artery 
(figs. 2, 3, and 6, ws. art). 
The second branch first gives off a vessel running ventrally and supplying the 
muscles ventrad of the afferent vessels and then bifurcates. One of the resultant 
vessels passes to the anterior wall of the pericardium (fig. 6, fevz. a7t.), the other 
runs to the ventral side of the conus arteriosus, and then penetrating the muscle wall 
of the latter can be traced as far as its union with the ventricle. This forms the 
coronary artery and I have been unable to detect any corresponding branch from the 
hypobranchial artery of the left side (figs. 2, 3, and 6, cov. avt.). 
With the two exceptions above described the efferent vessels of the branchial 
arches end blindly on the ventral surface, those of consecutive arches not being 
definitely united together as they are in such an Elasmobranch as Mustelus.* In 
this respect again the Dipnoi agree with Teleostei and Amphibia. As stated above, 
in the development of Rana the efferent artery of the first branchial arch becomes 
directly continuous ventrally with the lingual artery, though probably both in the 
ease of Amphibia and of Ceratodus this is not a primitive feature, but one due to 
modification of the blood vessels following on suppression of the gills in front of the 
branchial arches. 
(c) Anterior carotid artery (figs. 2 and 5). 
The artery which from its distribution appears to be the equivalent of the vessel 
of this name in fishes is in direct connection with the hyoidean hemibranch. The 
small vessels in the laminz of the latter open into a collecting vessel (= post-efferent 
vessel of other arches ?), and from about the middle of the length of this, at the 
level where the hyoidean artery enters, the anterior carotid arises. Its origin is 
* Cf. Parker, Phil. Trans. R. S. 1886, pl. xxxty. and xxxy. figs. 1 and 6, 
